Due to the narrow emission peaks of quantum dots, the emission wavelength can vary with the size conditions and is currently widely used in the backlight products. However, as the quantum dots are exposed to the water and oxygen environment, there is an irreversible and rapid decrease in the fluorescence efficiency. The package of the quantum dots requires good isolation from water and oxygen. At present, PET sheets with barrier films are configured on and beneath the quantum dot sheet. In order to make the quantum dot sheet have stable optical properties and service life, the oxygen barrier capacity of the barrier films needs to reach <10−1 cc/m^2·day, and the water permeability also needs to reach <10−1 g/m^2·day. In addition, because the quantum dots are sensitive to temperature, once the temperature increases, the wavelength of the quantum dots will have a red shift, and the luminous efficiency will also decrease.
As shown in FIG. 1, the conventional light emitting diode utilizes a metal bracket 11 and a plastic bracket 12. The light emitting diode chip 13 is fixed on the metal bracket 11 and connected to the metal bracket 11 with the gold wires 14. The phosphor and silicone gel 15 are packaged on the metal bracket 11 and the plastic bracket 12 with the packaging glue 16. Since the oxygen permeability and water permeability of the plastic bracket 12 and the packaging glue 16 do not meet the requirements of the quantum dot working environment, and the thermal conductivities of the plastic bracket 12 and the packaging glue 16 are lower. It causes the temperature of the quantum dots to increase, and the quantum dots may decrease in luminous efficiency when the temperature increases.